Romeoville Illinois Climate Data

Monthly Average Climate Data for Romeoville Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January16.3 °F31.6 °F2.15 in.
February19.0 °F35.5 °F2.0 in.
March28.6 °F47.4 °F2.55 in.
April39.1 °F60.4 °F4.0 in.
May50.0 °F71.3 °F4.86 in.
June60.1 °F80.8 °F4.71 in.
July64.2 °F84.5 °F4.24 in.
August62.8 °F82.6 °F4.24 in.
September55.0 °F76.9 °F3.32 in.
October42.8 °F63.7 °F3.52 in.
November32.0 °F49.2 °F2.5 in.
December22.0 °F36.8 °F2.22 in.
Annual41 °F60.1 °F40.31 in.

Climate Data for Romeoville Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 1 - May 10
Average Days With Frost100-125 Days
Plant Hardiness Zone - 2023Zone 6a : -10°F to -5°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation